Note: Descriptions are shown in the official language in which they were submitted.
0800090-5/90141752
METHOD, PROCESS AND SYSTEM FOR RECYCLING
AN ASPHALT-BASED ROOFING MATERIAL
TECHNICAL FIELD
[0001] The present disclosure generally relates to methods, processes and
systems
for the recycling of asphalt-based roofing materials. In particular, the
present disclosure
generally relates to methods, processes and systems to separate the
constituents of an
asphalt-based roofing shingle and recover and reuse such constituents in
various
applications.
BACKGROUND
[0002] A significant amount of unwanted material is generated from
the manufacture,
installation and removal of asphalt-based materials, such as roofing shingles.
For example,
an average residential roof removal generates 1-3 tons of roofing shingles,
depending on
whether the old roof consisted of 1 or 2 layers. All this adds up to an
estimated total of
approximately 13.5 million tons of torn-off shingles every year nationwide in
North America,
plus an additional 1 million tons of scrap generated by the shingle
manufacturing process.
This is a huge amount of unwanted material destined for already overcapacity
landfills,
especially since torn-off roofing shingles take at least 300 years to break
down and as such
some jurisdictions are increasing disposal fees, limiting disposal limits to
very low percentages
or banning completely. Moreover, roofing shingles cannot be composted and
burning or
incineration is not recommended, as it may result in the emissions of gases
hazardous to
human health. Since the materials in roofing shingles are similar to those
materials used in
hot mix asphalt cement and other road applications, unwanted roofing shingles
have been
identified as a material that may be diverted from landfill disposal and
recycled and reused,
however use in road applications is limited to very low percentages in some
jurisdictions or
completely banned in others.
[0003] A roofing shingle is typically made up of different materials,
including cellulose
(paper) or a fiberglass mat, an asphalt coating and a layer of aggregate
granules dispersed
on the coating. Developing technically viable and cost-effective recycling
processes has
proven to be challenging since these materials are difficult to break
down/separate and
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therefore typically require complex process steps or equipment. For example,
the asphalt and
aggregate strongly adheres to one another making their separation difficult. A
further problem
associated with efforts to recycle these materials concerns the difficulty in
shredding the
shingles on a bulk basis. Because of their high granular material content,
roofing shingles act
like large pieces of sandpaper and as such, large piles of roofing shingles
are extremely
difficult to drag, flow, separate, or handle. Additionally, recycling of
roofing shingles normally
requires modification to standard grinding, screening, separation and dust
control equipment
in order to reach the desired end use products.
[0004] Some past recycling processes have used milling machines, such
as rolling
mills, bag mills, hammer mills, saw mills, etc. to produce a recycled roofing
material which can
only be used in road construction or as other similar "filler" material. Other
processes have
used a solvent to break down the roofing shingle, for example, U.S. Pat. No.
8,789,773
discloses a process, in which a solvent is first added to an asphalt-based
material to form a
mixture containing asphalt dissolved in solvent and a solids material. The
solids material can
be separated out by centrifugation or filtration while the asphalt dissolved
in solvent can be
fractionally distilled to separate the heavier asphalt phase from the lighter
solvent phase. In
WO 2020/041347, a process is disclosed that includes contacting a roofing
shingle with a
petroleum chemical in a screened tubular rotating apparatus to separate
asphalt from the
sand and fiberglass. U.S. Pat. App. Publ. No. 2019/0256783 also discloses a
process
whereby roofing shingles are placed in a dissolution vessel and a solvent
stream is added to
the vessel to dissolve the asphalt under agitation to yield a solids rich
stream and a solvent
and bitumen rich stream which can be passed through a flash drum to yield a
solvent rich
stream and a bitumen rich stream. Finally, U.S. Pat. No. 4,222,851 discloses a
process in
which roofing shingles are repeatedly washed with solvent and the solvent and
asphalt are
subsequently separated from one another in first and second stage evaporators.
[0005] Nevertheless, there is a continuing need to provide improved
methods and
processes in which torn-off roofing shingles and shingle material which is the
by-product of
the manufacture of new roofing shingles can be recycled and reused, thus
avoiding landfill.
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SUMMARY
[0006] According to an embodiment of the present disclosure, there is
provided a
method for removing aggregate from an asphalt-based roofing material by: (a)
contacting the
asphalt-based roofing material with at least one pressurized stream of fluid
to mechanically
separate the aggregate from the asphalt-based roofing material and (b)
agitating or pulsing
the separated aggregate, asphalt-based roofing material and fluid in a
separation tank to
remove the separated aggregate from the asphalt-based roofing material and
fluid by density.
[0007] In some embodiments, the asphalt-based roofing material is
contacted with the
at least one pressurized stream of fluid within the separation tank or
externally in a separate
vessel.
[0008] In some embodiments, the asphalt-based roofing material is
contacted with at
least two pressurized streams of fluid. In some embodiments the at least two
pressurized
streams of fluid are opposed to one another.
[0009] In some embodiments, the fluid comprises water. In some
embodiments, the
fluid is at ambient temperature.
[0010] In some embodiments, the asphalt-based roofing material is
pretreated to
crush or grind the asphalt-based roofing material.
[0011] In some embodiments, the method further comprises the step of
recovering the
separated aggregate. In some embodiments, least about 90 wt.% of a total
weight of
aggregate originally present in the asphalt-based roofing material is
recovered as separated
aggregate.
[0012] According to another embodiment, there is provided a method
for separating
fiber from an aggregate-free asphalt-based roofing material, by: (a) mixing
the aggregate-free
asphalt-based roofing material with a solvent to form a slurry and (b) machine
pressing or filter
pressing the slurry in a fiber separator to separate fiber from the slurry and
produce an
asphalt/solvent mixture and a fiber product. The aggregate-free asphalt-based
roofing
material was obtained by contacting an asphalt-based roofing material with at
least one
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pressurized stream of fluid to remove substantially all aggregate from the
asphalt-based
roofing material.
[0013] In some embodiments, the solvent is selected from an aromatic
solvent, an
aliphatic solvent, an alcohol, an ether, a ketone, carbon disulfide and a
mixture thereof. In
some embodiments, a mass fraction of solvent mixed with the aggregate-free
asphalt-based
roofing material is in a range of about 15-50 wt.% relative to the total
weight of the slurry.
[0014] In some embodiments, the fiber separator is a rotary press, a
belt press, a
hydraulic press, a piston press, a hydrocyclone or a screw press.
[0015] In some embodiments, the aggregate-free asphalt-based roofing
material was
obtained by contacting an asphalt-based roofing material with at least one
pressurized stream
of fluid to remove substantially all aggregate from the asphalt-based roofing
material and
drying the asphalt-based roofing material.
[0016] In some embodiments, the fiber product is substantially free
of asphalt.
[0017] In still another embodiment, there is provided a method for
recovering an asphalt
product from an asphalt/solvent mixture by: (a) passing the asphalt/solvent
mixture through a
solvent separator to separate the asphalt product from the solvent and (b)
removing the
asphalt from the solvent separator. The asphalt in the asphalt/solvent mixture
was derived
from an asphalt-based roofing material and is substantially free of aggregate
and fiber.
[0018] In some embodiments, the solvent separator is a distillation
unit or evaporator.
In some embodiments, solvent separator is a wiped film evaporator. In some
embodiments,
the solvent comprises an aromatic solvent.
[0019] In some embodiments, step (a) is performed at a temperature
between about
155 C to about 165 C and at atmospheric pressure.
[0020] In some embodiments, at least about 80 wt.% of a total weight
of asphalt
originally in the asphalt-based roofing material is recovered as the asphalt
product.
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[0021] In some embodiments, there is provided an asphalt product
produced
according to the above-described methods.
[0022] In still another embodiment, there is provided a system for
producing at least
an asphalt product from an asphalt-based roofing material containing a
plurality of roofing
shingles, the system comprising (a) an aggregate removal unit operable to
remove
substantially all aggregate from the asphalt-based roofing material to produce
an aggregate-
free asphalt/fiber mixture, (b) a fiber separation unit operable to mix the
aggregate-free
asphalt/fiber mixture with a solvent to produce a slurry and to remove
substantially all fiber
from the slurry to produce an asphalt/solvent mixture and (c) a solvent
separation unit
operable to separate substantially all solvent from the asphalt to produce an
asphalt product.
[0023] In some embodiments, the aggregate removal unit comprises a
separation tank
configured to receive and combine the asphalt-based roofing material and at
least one or more
pressurized streams of a first fluid and to agitate or pulse a mixture of
aggregate, a second
fluid and the aggregate-free asphalt/fiber mixture. In some embodiments, the
aggregate
removal unit further comprises a dewatering or drying apparatus configured to
remove
moisture from the asphalt/fiber mixture.
[0024] In some embodiments, the fiber separation unit comprises a
mixing tank
configured to receive and combine the aggregate-free asphalt/fiber mixture and
a solvent and
produce an asphalt/fiber/solvent slurry. In some embodiments, the fiber
separation unit further
comprises a fiber separator configured to receive the asphalt/fiber/solvent
slurry and separate
fiber from the asphalt/fiber/solvent slurry and produce an asphalt/solvent
mixture and a fiber
product.
[0025] In some embodiments, the solvent separation unit comprises a
solvent
separator configured to receive the asphalt/solvent mixture and heat the
mixture to separate
the solvent from the mixture and produce the asphalt product. In some
embodiments, the
solvent separation unit further comprises a condenser configured to recover
the solvent
separated from the mixture.
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[0026] In some embodiments, the system further comprises a
pretreatment unit
comprising a grinder operable to reduce the particle size of the asphalt-based
roofing material
and a feed system to deliver the asphalt-based roofing material to the
aggregate removal unit.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] In drawings which illustrate embodiments of the invention,
[0028] FIG. 1 is a schematic block diagram of a method for recycling
an asphalt-based
roofing material according to an embodiment of the present disclosure; and
[0029] FIG. 2 schematically illustrates a system for producing an
asphalt product from
an asphalt-based roofing material according to another embodiment of the
present disclosure.
DETAILED DESCRIPTION
[0030] The following terms shall have the following meanings:
[0031] The term "comprising" and derivatives thereof are not intended
to exclude the
presence of any additional component, step or procedure, whether or not the
same is
disclosed herein. In order to avoid any doubt, all compositions claimed herein
through use of
the term "comprising" may include any additional additive or compound, unless
stated to the
contrary. In contrast, the term, "consisting essentially of" if appearing
herein, excludes from
the scope of any succeeding recitation any other component, step or procedure,
except those
that are not essential to operability and the term "consisting of", if used,
excludes any
component, step or procedure not specifically delineated or listed. The term
"or", unless
stated otherwise, refers to the listed members individually as well as in any
combination.
[0032] The articles "a" and "an" are used herein to refer to one or
to more than one
(i.e., to at least one) of the grammatical objects of the article. By way of
example, "a solvent"
means one solvent or more than one solvent. The phrases "in one embodiment",
"according
to one embodiment" and the like generally mean the particular feature,
structure, or
characteristic following the phrase is included in at least one embodiment of
the present
disclosure and may be included in more than one embodiment of the present
disclosure.
Importantly, such phrases do not necessarily refer to the same aspect. If the
specification
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states a component or feature "may", "can", "could", or "might" be included or
have a
characteristic, that particular component or feature is not required to be
included or have the
characteristic.
[0033] The term "about" as used herein can allow for a degree of
variability in a value
or range, for example, it may be within 10%, within 5%, or within 1% of a
stated value or of a
stated limit of a range.
[0034] Values expressed in a range format should be interpreted in a
flexible manner
to include not only the numerical values explicitly recited as the limits of
the range, but to also
include all of the individual numerical values or sub-ranges encompassed
within that range as
if each numerical value and sub-range is explicitly recited. For example, a
range such as from
1 to 6, should be considered to have specifically disclosed sub-ranges, such
as, from 1 to 3,
from 2 to 4, from 3 to 6, etc., as well as individual numbers within that
range, for example, 1,
2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.
[0035] The terms "preferred" and "preferably" refer to embodiments
that may afford
certain benefits, under certain circumstances. However, other embodiments may
also be
preferred, under the same or other circumstances. Furthermore, the recitation
of one or more
preferred embodiments does not imply that other embodiments are not useful,
and is not
intended to exclude other embodiments from the scope of the present
disclosure.
[0036] The term "optional" or "optionally" means that the
subsequently described
event or circumstance may or may not occur, and that the description includes
instances
where said event or circumstance occurs and instances where it does not.
[0037] The term "substantially free" refers to a composition in which
a particular
constituent or moiety is present in an amount that has no material effect on
the overall
composition. In some embodiments, "substantially free" may refer to a
composition in which
the particular constituent or moiety is present in the composition in an
amount of less than
about 10 wt.% or less than about 5 wt.%, or less than about 4 wt.%, or less
than about 3 wt.%
or less than about 2 wt.% or less than about 1 wt.%, or less than about 0.5
wt.%, or less than
about 0.1 wt.%, or less than about 0.05 wt.%, or even less than about 0.01
wt.% based on the
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total weight of the composition, or that no amount of that particular
constituent or moiety is
present in the respective composition.
[0038] The term "substantially" means a proportion of at least about
60%, or
preferably at least about 70% or at least about 80%, or at least about 90%, at
least about 95
wt.%, at least about 97% or at least about 99% or more, or any integer between
about 70%
and about 100%. For example, removing substantially all of a component from a
composition
may be the removal of at least about 60 wt.% or at least about 70 wt.%, etc.
of the component
from the composition.
[0039] The term "wt.%" means weight percent.
[0040] The term "integrated process" means a process where two or more
related
process steps of at least two separate industrial processes, which can be
separately
performed, are combined, so that at least one process step is common for the
two processes.
Moreover, in an "integrated process" as defined herein streams, fractions
and/or portions
produced and/or obtained in one industrial process can be used in another
industrial process
thereby improving the overall process efficiently more than the sum of each
individual process.
The integrated process reuses certain materials and streams and reduces by-
products that
otherwise would require treatment. In other words, the term "integrated
process" means a
combination of at least two unit operations which exploits the interactions
between different
units in order to employ resources effectively, improve energy efficiency,
improve material
balance, maximize profit and/or minimize costs. At least one of the two unit
operations
receives material and/or energy, and may be dependent on these, from the other
unit
operation. In an integrated process the interactions between different unit
operations are
considered from the outset, rather than having them optimized separately.
Process
integration is not limited to the design of new plants, but it also covers
retrofit design, for
example new units to be installed in an old plant, and the operation of
existing systems.
[0041] The term "asphalt-based roofing material" as used herein may
refer to any new
or used material that is used in connection with roofing and that contains a
proportion of
asphalt, such as for example, new or torn off (used) roofing shingles (which
may be organic
or fiberglass), new or used roofing felt or tar paper, flat roof material
(which may include felt,
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aggregate and bitumen or asphalt sealant), unwanted material from the
production of new
roofing shingles or unwanted material from the installation of roofing
shingles on residential
or commercial buildings. In addition to asphalt, the asphalt-based roofing
material may further
include a proportion of aggregate and fiber. For example, a roofing shingle
may include from
about 45-55 wt.% aggregate, from about 20-30 wt.% fiber and from about 20-30
wt.% asphalt,
based on the total weight of the roofing shingle.
[0042] The term "asphalt" may refer to any type of bituminous
material suitable for use
on a roofing material or pavement, such as asphalts, tars, pitches, or
mixtures thereof. The
asphalt may be either manufactured asphalt produced by refining petroleum or
naturally
occurring asphalt. The asphalt can be oxidized or non-oxidized. The asphalt
may include any
number of various additives and/or modifiers, such as inorganic fillers or
mineral stabilizers,
organic materials such as polymers, recycled streams, and/or ground tire
rubber.
[0043] The term "aggregate" may refer to solid particles having a
range of sizes
including fine particles to relatively coarse particles, for example sand,
crushed stone, gravel,
slag, or other mineral granules.
[0044] The term "fiber" as used herein may refer to a solid fibrous
material such as
glass fiber or paper (cellulose) fiber. The term may refer to a mat of
interwoven fiber strands
when present in roofing shingles, or to a mixture of individual strands and/or
particles of fiber.
[0045] The term "asphalt/fiber slurry" as used herein may refer to a
mixture of asphalt,
fiber (which may include fiber particles alone or partially or completely
coated with asphalt),
and a fluid.
[0046] The term "asphalt/fiber mixture" as used herein may refer to a
mixture of
asphalt and fiber derived from an asphalt-based roofing material. The
asphalt/fiber mixture
may include asphalt, fiber and fiber partially or completely coated with
asphalt. The
asphalt/fiber mixture may also contain a proportion of a fluid but which
proportion is less than
the proportion of fluid present in the asphalt/fiber slurry defined above.
[0047] The term "asphalt/fiber/solvent slurry" as used herein may
refer to a mixture of
fiber carried by a mixture of asphalt and a solvent (or a blend of more than
one solvent).
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[0048] The term "asphalt/solvent mixture" as used herein may refer to
a mixture of
asphalt and a solvent (or a blend of more than one solvent), where the asphalt
may be fully
or partially miscible with the solvent or dispersed within the solvent.
[0049] The present disclosure generally relates to a method and
integrative process
for recycling an asphalt-based roofing material and to a system for producing
an asphalt
product from such an asphalt-based roofing material. It has been surprisingly
found that the
method, process and system of the present disclosure can break down and
effectively
separate the constituents of the asphalt-based roofing material (such
constituents having
been combined together to produce the asphalt-based roofing material) using
minimal
equipment and without having to input large amounts of energy. Thus, the
methods,
integrative process and system of the present disclosure are more economical
and
environmentally friendlier than state of the art methods, processes and
systems. Additionally,
because the constituents of the asphalt-based roofing material are effectively
separated from
each other in high yields and purities, they can be repurposed/used in a wide
range of
applications. Thus, the inventive method, integrative process and system of
the present
disclosure avoid the need of having to sanitarily dispose a substantial amount
of unwanted
material generated during the shingle manufacturing process or during the
shingling or re-
shingling of a roof.
[0050] With reference to FIG.1, a method 100 for recycling the
asphalt-based roofing
material, which according to an embodiment includes at least a plurality of
roofing shingles
102, is shown and may generally include steps 104 to 108. In step 104,
aggregate is removed
from the asphalt-based roofing material mechanically and by density to produce
an
asphalt/fiber mixture 112 and an aggregate product 110. In some embodiments,
the method
may optionally include a step of mechanically reducing the size of the asphalt-
based roofing
material prior to step 104. In some embodiments, the asphalt/fiber mixture 112
that is
produced in step 104 is substantially free of aggregate. In step 106, a
solvent 114 is added
to the asphalt/fiber mixture 112 to produce an asphalt/fiber/solvent slurry
and the slurry is
machine pressed to remove fiber from the slurry to produce an asphalt/solvent
mixture 118
and a fiber product 116. In some embodiments, the asphalt/solvent mixture that
is produced
in step 106 is substantially free of fiber or aggregate or fiber and
aggregate. In step 108, the
solvent is separated from the asphalt/solvent mixture 118 to produce an
asphalt product 120.
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In some embodiments, the asphalt product 120 that is produced in step 108 is
substantially
free of solvent or fiber or aggregate or solvent and fiber and aggregate. In
further
embodiments, the solvent that is separated from the asphalt/solvent mixture in
step 108 may
be recovered and reused in step 106.
[0051] According to another embodiment, a system 200 operable for
performing the
method above to produce at least an asphalt product 218 from an asphalt-based
roofing
material containing a plurality of roofing shingles 202, is generally shown in
FIG. 2. The
system 200 may be controlled by a controller (not shown) configured to control
some or all of
the operations described below. In particular, the controller may be
configured to execute
computer code for performing the operations described herein. In this regard,
the controller
may comprise a processor that may be a microprocessor or a controller for
controlling the
overall operation thereof. In one embodiment the processor may be particularly
configured to
execute program code instructions related to the functions described herein.
The
controller may also include a memory device. The memory device may include non-
transitory
and tangible memory that may be, for example, volatile and/or non-volatile
memory. The
memory device may be configured to store information, data, files,
applications, instructions
or the like. For example, the memory device could be configured to buffer
input data for
processing by the processor. Additionally or alternatively, the memory device
may be
configured to store instructions for execution by the processor.
[0052] The controller may also include a user interface that allows a user
to interact
therewith. For example, the user interface can take a variety of forms, such
as a button,
keypad, dial, touch screen, audio input interface, visual/image capture input
interface, input in
the form of sensor data, etc. Still further, the user interface may be
configured to output
information to the user through a display, speaker, or other output device. A
communication
interface may provide for transmitting and receiving data through, for
example, a wired or
wireless network such as a local area network (LAN), a metropolitan area
network (MAN),
and/or a wide area network (WAN), for example, the Internet. The communication
interface may enable the controller to communicate with one or more further
computing
devices, either directly, or via a network. In this regard, the communication
interface may
include one or more interface mechanisms for enabling communication with other
devices
and/or networks. The communication interface may accordingly include one or
more interface
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mechanisms, such as an antenna (or multiple antennas) and supporting hardware
and/or
software for enabling communications via wireless communication technology
(e.g., a cellular
technology, communication technology, Wi-Fi and/or other IEEE 802.11
technology,
Bluetooth, Zigbee, wireless USB, NFC, RF-ID, WiMAX and/or other IEEE 802.16
technology,
and/or other wireless communication technology) and/or a communication modem
or other
hardware/software for supporting communication via cable, digital subscriber
line (DSL), USB,
FireWire, Ethernet, one or more optical transmission technologies, and/or
other wireline
networking methods. Further, the controller may include various modules which
may be
configured to, in conjunction with the processor, direct operations for
removing the aggregate
from the roofing shingles in the aggregate removal unit, separating the fiber
in the fiber
separator unit and/or separating the solvent in the solvent separator unit to
ultimately produce
the asphalt product as described herein.
[0053]
As illustrated, the system 200 may include an aggregate removal unit 204. The
aggregate removal unit 204 is operable to perform step 104 above and may
include a
separation tank 222 configured to receive and combine the roofing shingles 202
and at least
one or more pressurized streams of fluid 224. The separation tank 222 may also
be
configured to agitate or pulse a mixture of a fluid (which may be the same
fluid as the
pressurized stream of fluid or a different fluid), the roofing shingles and
aggregate that may
be contained therein. The aggregate removal unit 204 may further include a
dewatering
and/or drying apparatus 228 configured to receive the mixture contained in the
separation
tank 222 and to remove moisture from the mixture. Thus, as will be described
in more detail
below, the separation tank 222 is configured to receive and combine the
roofing shingles 202
and one or more pressurized streams of fluid 224 and to agitate or pulse the
mixture of fluid,
roofing shingles and aggregate to produce an asphalt/fiber slurry 226 and an
aggregate
product 210. The dewatering and drying apparatus 228 is configured to receive
the
asphalt/fiber slurry 226 and remove moisture from the asphalt/fiber slurry 226
to produce an
asphalt/fiber mixture 212.
In some embodiments, the moisture that is removed in the
dewatering and drying apparatus 228 may be recovered and reused in system 200.
[0054]
The system 200 may also include a fiber separation unit 206. The fiber
separation unit 206 is operable to perform step 106 above and may include a
mixing tank 232
configured to receive and combine the moisture-removed mixture from the
aggregate removal
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unit 204 and a liquid. The fiber separation unit 206 may further include a
fiber separator 236
configured to receive the contents in the mixing tank 232 and separate solids
from liquids.
Thus, as will be described in more detail below, the mixing tank 232 is
configured to receive
and combine the asphalt/fiber mixture 212 and a solvent 230 to produce an
asphalt/fiber/solvent slurry 234. The fiber separator 236 is configured to
receive the
asphalt/fiber/solvent slurry and separate fiber from the asphalt/fiber/solvent
slurry 234 to
produce an asphalt/solvent mixture 216 and a fiber product 214.
[0055] Finally, the system 200 may include a solvent separation unit
208. The solvent
separation unit 208 may be used to perform step 108 above and may include a
solvent
separator 238 configured to receive a mixture of liquids and heat the mixture
to separate the
liquids in the mixture. Thus, as will be described in more detail below, the
solvent separator
238 is configured to receive the asphalt/solvent mixture 216 and heat the
mixture to separate
the solvent from the mixture to produce an asphalt product 218. In some
embodiments, the
solvent separation unit may further include a condenser configured to condense
and recover
the solvent separated from the mixture so that it can be reused in the system
200.
[0056] In a further embodiment, the system 200 may optionally include
a pretreatment
unit (not shown). The pretreatment unit may include a grinder that is operable
to crush or
grind the asphalt-based roofing material as needed based on production and
availability in
order to reduce the roofing material to a desired particle size (for e.g., to
a maximum of less
than about 1 inch). In one embodiment, the particle size is screened to 3/4
inch minus (i.e., 3/4
of an inch or less). It should be noted that the particles are generally
irregularly shaped. In
some embodiments, the asphalt-based roofing material may first be cleaned of
nails and other
debris by hand or by using a magnet before being sent to the grinder. In other
embodiments,
nails and debris maybe removed after the feed hopper or after first stage of
separation. The
pretreatment unit may further include a feed system configured to receive the
asphalt-based
roofing material from the grinder and which may be interlocked with other
plant components
and controlled by the controller. The feed system may include a feed hopper
which may be
equipped with a drive motor, a strainer (e.g., comprising one or more
screens), and one or
more conveyors (e.g., comprising an auger). The feed system may be calibrated
to regulate
flow of the asphalt-based roofing material to the aggregate removal unit 204
as controlled by
the controller.
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Removal of Aggregate (Step 104) in the Aggregate Removal Unit (204)
[0057] As described above, in step 104 aggregate is removed from the
roofing
shingles 102 to produce the aggregate product 110 and the asphalt/fiber
mixture 112. In the
embodiment shown in FIG. 2, this removal may be accomplished in the aggregate
removal
unit 204 mechanically and by density by physically contacting the roofing
shingles 202 with
one or more pressurized streams of fluid 224 in the separation tank 222 to
separate aggregate
from the roofing shingles and by agitating or pulsing the mixture of fluid,
roofing shingles and
separated aggregate contained within the separation tank 222. In other
embodiments the
roofing shingles may be physically contacted with the one or more pressurized
streams of
fluid 224 prior to the separation tank 222.
[0058] The separation tank 222 may be shaped, sized and configured to
hold any
suitable volume of fluid and is also operable to agitate or pulse the fluid
contained therein and
therefore may include an inner cavity and a mixing device. Examples of mixing
devices
include, but are not limited to, vanes, paddles, blades, screw elements, or
other elements of
dynamic mixers such as rotating or co-rotating screw mixers, planetary and
double planetary
mixers, impellers, and the like or baffle elements within a static mixer, such
as plates, helices,
vanes, paddles, or blades, intended to disrupt laminar flow and cause mixing
within the static
mixer. In an embodiment, the mixing device is a is a movable paddle or block
that creates an
up and down or side to side movement within separation tank 222 to pulse the
fluid in the
separation tank 222. The separation tank 222 may be in fluid communication
with one or
more sources of fluids (such as a holding or buffer tank) via one or more
conduits which supply
the one or more pressurized streams (or jets) of fluid 224 to the separation
tank 222. Each
stream of fluid 224 supplied to and received by the separation tank 222 may be
the same fluid
or a different fluid.
[0059] The roofing shingles 202 may be introduced into some, or all, of the
one or
more pressurized streams of fluid 224 supplied to the separation tank 222 by
any suitable
method. For example, the roofing shingles 202 may be supplied to a funnel or
hopper as
described above that is in communication with some, or all, of the one or more
streams of fluid
224. The controller may control the amount of the roofing shingles 202 which
are contacted
.. by a stream of fluid 224. Contact between the roofing shingles 202 and the
streams of fluid
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224 may be of sufficient force to dislodge aggregate from the roofing shingles
202 such that
aggregate is separated from the roofing shingles 202. In addition, the force
may be sufficient
to dislodge asphalt that is adhered to and coating the aggregate such that
aggregate that is
separated is substantially free of adhered asphalt.
[0060] The elevated flow rate and/or pressure of the one or more streams of
fluid 224
entering the separation tank 222 may be sufficient to cause cavitation of the
fluid within
separation tank 222. As is well known, cavitation is a phenomenon in which the
local static
pressure of a fluid is reduced to below the vapor pressure of the fluid
causing the formation of
small vapor filled cavities (or bubbles) within the fluid. Thus, one or more
fluid conduits that
supply the streams of fluid 224 to separation tank 222 may be configured to
produce Venturi
effects via a relatively narrow or constricted section within the conduit
followed by a wider
section that is positioned close to the outlet. As the stream of fluid 224
passes through the
constricted section, the pressure of the fluid will decrease as the flow rate
increases. The
combination of pressure and kinetic energy can create a cavitation cavern
downstream of the
constriction generating high energy cavitation bubbles. These cavitation
bubbles may
subsequently collapse, generating shockwaves waves within the fluid. As these
shockwaves
contact roofing shingles 202 within separation tank 222, a cavitation force is
applied to roofing
shingles 202 sufficient to separate aggregate from the other constituents of
the roofing
shingles 202. The cavitation force may also be sufficient to dislodge asphalt
adhered to and/or
coating the aggregate particles such that the aggregate is substantially free
of asphalt.
[0061] Further, each of the one or more fluid conduits may be
positioned such that the
outlet of each of the one or more conduits is generally directed towards the
outlet of another
of the one or more conduits. This means that one stream of fluid 224 exiting
from one conduit
will collide with another stream of fluid 224 exiting from another conduit
within separation tank
222. This may further increase the turbulent flow of fluid 224 within
separation tank 222 and
may also increase contact between roofing shingles 202 and stream of fluid 224
to assist in
separating aggregate from the roofing shingles 202.
[0062] In one embodiment, the separation tank 222 may have one pair
of conduits,
where the outlet of the first conduit may be generally directed towards the
outlet of the second
Date Recue/Date Received 2022-09-29
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conduit such that the stream of fluid 224 exiting through the outlet of the
first conduit will collide
with the stream of fluid 224 exiting through the outlet of the second conduit.
[0063] In other embodiments, the separation tank 222 may have more
than one pair
of conduits where the outlet of the first conduit in each pair may be
generally directed towards
the outlet of the second conduit in each pair. For example, the separation
tank 222 may have
2, 4, 6, 8, 10, 12 or more pairs of conduits where the outlet of the first
conduit in each pair
may be generally directed towards the outlet of the second conduit in each
pair. Each of the
pairs of conduits may be positioned at different locations in separation tank
222, for example
each pair of conduits may be vertically spaced from the next pair of conduits.
[0064] In still other embodiments, in each of the pairs of conduits
described above,
the outlet of the first conduit may directly oppose the outlet of the second
conduit in each pair.
This may increase the contact between the opposing streams of fluid,
increasing the number
and the force of collisions between the roofing shingles 202 and streams of
fluid 224.
[0065] In a further embodiment, the separation tank 222 may include
more than two
conduits with outlets generally directed towards each other. For example, the
separation tank
222 may have three conduits, where the outlets of the first, second and third
conduits are
directed towards each other. In other embodiments, separation tank 222 may
have 4, 5 or 6
or more conduits all having outlets directed towards each other.
[0066] In another embodiment, the separation tank 222 may have a
single conduit,
where the outlet of the single conduit is generally directed towards an impact
surface such as
a contact plate, or the inner surface of separation tank 222. The use of an
impact surface
other than the inner surface of separation tank 222 may be preferable to
reduce wear of the
inner surface of separation tank 222 caused by impact of the stream of fluid
224. The force
of the stream of fluid impacting the contact plate may be of sufficient force
to dislodge
aggregate from the roofing shingles 202 and/or cause cavitation of the fluid
within separation
tank 222 as described above.
[0067] In further embodiments, the separation tank 222 may have
multiple sets of
single conduits where the outlets of the single conduits are generally
directed towards an
impact surface. For example, the separation tank 222 may have 2, 3, 4, 5, 6,
7, 8 or more
16
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sets of single conduits where the outlets of the single conduits are generally
directed towards
an impact surface.
[0068] In still other embodiments, for each impact surface in the
separation tank 222
there may be more than one conduit where the outlet of each conduit is
generally directed
towards the impact surface. For example, each impact surface may have 2, 3, 4,
5 ,6 or more
conduits where the outlet of each conduit is generally directed towards the
impact surface.
[0069] The separation tank 222 is further configured to agitate or
pulse a mixture of
fluid, aggregate and roofing shingles contained therein. Agitation may be
achieved by any
known mixing device as described above, such as for example, by rotation of a
paddle or
impeller configured to circulate the roofing shingles that have fallen towards
the lower region
of the separation tank 222 (and into the fluid contained therein) in the
mixture in a generally
upwards direction. By increasing the contact time of the roofing shingles 202
and fluid via
agitation or pulsing, separation of aggregate from the roofing shingles 202
may be further
increased in separation tank 222.
[0070] In one embodiment, the pressure of the one or more pressurized
streams of
fluid 224 supplied to and received by the separation tank 222 may range
between about 100
psi to about 150 psi, or about 105 psi to about 145 psi, or about 110 psi to
about 140 psi, or
about 115 psi to about 135 psi, or about 120 psi to about 130 psi. In an
embodiment, the flow
rate of the one or more pressurized streams of fluid 224 supplied to and
received by the
separation tank 222 may range between about 50 m3/hr to about 100 m3/hr, or
about 55 m3/hr
to about 95 m3/hr, or about 60 m3/hr to about 90 m3/hr, or about 65 m3/hr to
about 85 m3/hr,
or about 70 m3/hr to about 80 m3/hr.
[0071] In another embodiment, the separation tank 222 may be
generally cylindrical
and orientated vertically. In a specific embodiment, the separation tank 222
may have an
internal volume of about 10 m3 to about 100 m3, or about 20 m3 to about 90 m3,
or about 30
m3 to about 70 m3, or about 40 m3 to about 60 m3.
[0072] The fluid supplied to and received by the separation tank 222
as described
above may be selected from a fluid or blend of fluids having a lower specific
gravity than the
specific gravity of aggregate, such that, once the aggregate has been
separated from roofing
17
Date Recue/Date Received 2022-09-29
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shingles 202, it will migrate towards the lower end or bottom of separation
tank 222. An
aggregate product 210 may then be removed from such lower end or bottom of the
separation
tank 222 and further processed or repurposed as will be further described
below. The fluid or
blend of fluids may also have a specific gravity that is greater than the
specific gravity of the
remaining constituents of roofing shingles 202, namely a mixture of asphalt
and fiber, so that
this mixture will migrate to the upper end of separation tank 222 for removal
as an asphalt/fiber
slurry 226.
[0073] Furthermore, in some embodiments, the fluid or blend of fluids
described above
may also be immiscible with asphalt so that the asphalt present in the roofing
shingles 202 is
not lost through dissolution into the fluid or blend of fluids. For example,
in one embodiment
such fluid may include a glycol, such as ethylene glycol and propylene glycol.
In another
embodiment, the fluid may include an alcohol, such as a straight or branched
chain C1-C10
alcohol or mixture thereof. In another embodiment the C1-C10 alcohol is
ethanol, n-propanol,
isopropanol (IPA), n-butanol, propanol, or t-butanol. In yet another
embodiment the fluid may
comprise dimethylformamide (DMF), acetonitrile, acetone, tetrahydrofuran
dimethylsulfoxide
(DMSO), methylethylketone (ME K), or an aromatic solvent such as benzene,
methylbenzene
(toluene), dimethylbenzene or ethylbenzene.
[0074] In one specific embodiment, the fluid supplied to and received
by the
separation tank 222 via the one or more conduits comprises water. A
pressurized stream of
water may enter the separation tank 222 through the one or more conduits at a
pressure
ranging between about 100 psi to about 150 psi or about 105 psi to about 145
psi, or about
110 psi to about 140 psi, or about 115 psi to about 135 psi, or about 120 psi
to about 130 psi.
In an embodiment, the flow rate of the stream of water may range between about
50 m3/hr to
about 130 m3/hr, or about 55 m3/hr to about 125 m3/hr, or about 60 m3/hr to
about 120 m3/hr,
or about 65 m3/hr to about 115 m3/hr, or about 70 m3/hr to about 110 m3/hr or
about 75 m3/hr
to about 105 m3/hr or about 80 m3/hr to about 100 m3/hr or about 85 m3/hr to
about 95 m3/hr.
The pressure and flow rate may be selected so they are sufficient to cause
cavitation in the
separation tank 222.
[0075] In an embodiment, the fluid contained within the separation
tank 222 and/or
the one or more streams of fluid 224 contacting the roofing shingles 202 are
at ambient
18
Date Recue/Date Received 2022-09-29
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temperature. Aside from the lower energy input required, performing step 104
at ambient
temperatures may advantageously assist in the separation of aggregate from the
roofing
shingles 202 since at lower temperatures, the roofing shingles 202 tend to be
more brittle (and
less ductile) allowing the aggregate to separate from the roofing shingles 202
more easily.
[0076] In a further embodiment, the fluid contained in the separation tank
222 and/or
the one or more streams of fluid 224 contacting the roofing shingles 202 may
be at an elevated
temperature, i.e. a temperature that is greater than ambient temperature. The
elevated
temperature may be attained by any suitable method known in the art. For
example, the
separation tank 222 and or one or more conduits may include heating coils or
heat traces.
Alternatively, the streams of fluid 224 supplied to the separation tank 122
through the one or
more conduits may be preheated to an elevated temperature relative to the
fluid contained in
separation tank 222.
[0077] As described above, aggregate separated from the roofing
shingles 202 may
migrate towards the lower end or bottom of the separation tank 222 during
agitation. The
lower end of the separation tank 222 may have a tapered frustoconical shape
such that
separated aggregate is channeled towards the lower end of the separation tank
222 and
recovered from the separation tank 222 as an aggregate product 210. The
aggregate product
210 that is recovered may be dewatered and/or dried using any suitable means
known to
those skilled in the art, such as by passing the aggregate product 210 over a
vibrating
screen/shaker deck or by air drying. In some embodiments, moisture that is
removed during
drying may be collected, filtered or desilted in one or more purification
steps and then recycled
back to the separation tank 222.
[0078] The separation of aggregate from the roofing shingles 202
during step 104 may
be highly efficient such that substantially all of the aggregate originally
present in the roofing
shingles 202 is recovered from separation tank 222 as the aggregate product
210 and
therefore the roofing shingles 202 remaining in separation tank 222 are
substantially free of
aggregate, i.e., aggregate-free asphalt-based roofing shingles. According to
one
embodiment, at least about 90 wt.% of the total weight of aggregate originally
present in the
roofing shingles 202 is recovered as aggregate product 210. In other
embodiments at least
about 91 wt.%, or at least about 92 wt.%, or at least about 93 wt.%, or at
least about 94 wt.%,
19
Date Recue/Date Received 2022-09-29
0800090-5/90141752
or at least about 95 wt.%, or at least about 96 wt.%, or at least about 97
wt.%, or at least about
98 wt.%, or at least about 99 wt.% of the total weight of aggregate originally
present in roofing
shingles 202 is recovered as aggregate product 210.
[0079] As described above, the asphalt/fiber slurry 226 may be
removed from the
upper end of the separation tank 222. The upper end of the separation tank 222
may have a
tapered frustoconical shape such that the asphalt/fiber slurry 226 is
channeled towards the
central upper end of the separation tank 222 for easier removal.
[0080] The recovery of asphalt and fiber in the asphalt/fiber slurry
226 from the
separation tank 222 may be highly efficient such that the wt. ratio of asphalt
to fiber in the
asphalt/fiber slurry 226 is similar to the wt. ratio in the roofing shingles
202, i.e., about a 1:1
wt. ratio of asphalt to fiber. The asphalt/fiber slurry 226 also includes a
proportion of fluid.
According to an embodiment in which the fluid is water, the asphalt/fiber
slurry 226 can contain
at least about 80 wt.% water, based on the total weight of the asphalt/fiber
slurry for example,
at least about 81 wt.% water, at least about 82 wt.% water, at least about 83
wt.% water, at
least about 84 wt.% water, at least about 85 wt.% water, at least about 86
wt.% water, at least
about 87 wt.% water, at least about 88 wt.% water, at least about 89 wt.%
water, at least about
90 wt.% water, at least about 91 wt.% water, at least about 92 wt.% water, at
least about 93
wt.% water, at least about 94 wt.% water, at least about 95 wt.% water, based
on the total
weight of the asphalt/fiber slurry.
[0081] In another embodiment not shown in FIG. 2, the removal of aggregate
from
roofing shingles 202 and the separation of aggregate and asphalt/slurry 226
may occur in
separate locations. For example, roofing shingles 202 may first enter a first
tank where
contact with one or more streams of fluid 224 occurs in order to separate
aggregate in a similar
manner as described above. In this embodiment, separation of aggregate from
asphalt/fiber
slurry 226 does not occur in the same tank where cavitation occurs. Instead, a
mixture of
aggregate, asphalt/fiber slurry 126 and fluid may feed into a separation
apparatus in fluid
communication with the first tank, where separation of aggregate product 210
from
asphalt/fiber slurry 226 occurs. The separation apparatus may be any suitable
apparatus
operable to separate aggregate from asphalt/fiber slurry 226 such as a
separation tank, a
vertical or horizontal classification tank or a jig concentrator.
Date Regue/Date Received 2022-09-29
0800090-5/90141752
[0082] In an embodiment, the separation apparatus may be a jig such
as a water or
an air pulsed jig. A water jig may include an inclined jig bed (such as a
screen or sieve) within
a tank of fluid, such as fluid 224. A stream of aggregate and asphalt fiber
slurry 226 may be
fed on top of the jig bed at the higher end of the inclined jig bed. The fluid
within the tank may
be pulsed such that a column of fluid rises up through the jig bed, suspending
the particles
(e.g. the aggregate and asphalt/fiber particles) within the column of fluid.
When the fluid level
drops back down, the particles will be redeposited onto the jig bed. As the
pulsing of the fluid
is repeated, those particles with a higher specific gravity (i.e., aggregate)
will redeposit faster
than those particles with a lower specific gravity (i.e., asphalt/fiber). As
such, the aggregate
and asphalt/fiber will be separated by density and can be extracted from lower
end of jig bed
separately.
[0083] Referring to FIG. 2 the asphalt/fiber slurry 226 that is
recovered from the
separation tank 222 is sent to and received by a dewatering or drying
apparatus 228 where
fluid is removed from the asphalt/fiber slurry 226 to produce the
asphalt/fiber mixture 212.
Such removal can not only increase process efficiency but can also reduce
sludge and/or
emulsion formation from possibly occurring in subsequent steps 106 and 108 of
method 100.
[0084] The dewatering or drying apparatus 228 may be any suitable
type of dryer
equipment operable for removing a proportion of fluid from the asphalt/fiber
slurry 126. For
example, the drying apparatus 228 may be a vacuum dryer, tray dryer, fluidized
bed dryer,
rotary dryer, dewatering screen or spray dryer. In another embodiment, the
drying apparatus
228 is a centrifuge, for example a decanter centrifuge. The use of a decanter
centrifuge may
be preferred since it is able to operate at a high throughput while at ambient
temperature. In
still another embodiment, the drying apparatus 228 may be a hydrocyclone. The
asphalt/fiber
slurry 226 may first enter the hydrocyclone where a first proportion of the
fluid from the
.. asphalt/fiber slurry 226 is removed, for example from about 70-95 wt.% of
the total weight of
fluid present in asphalt/fiber slurry 226 is removed. The drying apparatus 228
may further
include a secondary drying apparatus, such as a fluidized bed dryer located
downstream of
the hydrocyclone, where a second proportion of fluid is removed from the
asphalt/fiber slurry.
[0085] In some embodiments, the fluid that is removed from the
asphalt/fiber slurry
.. 226 by the drying apparatus 228 may be recovered and recycled back to the
separation tank
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Date Recue/Date Received 2022-09-29
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228. When the fluid that is removed is water, such water may be treated to
remove impurities
before being recycled back to the separation tank 222. For example, suspended
solids in the
water may be removed using a de-silter prior to being recycled back to the
separation tank
222.
[0086] The dewatering or drying apparatus 228 may be configured and
operable to
remove only fluid from the asphalt/fiber slurry 226 and thus, substantially
all of the asphalt and
fiber in the asphalt/fiber slurry 226 may be recovered as asphalt and fiber in
the asphalt/fiber
mixture 212. In an embodiment, more than 80 wt.% of the total weight of
asphalt and fiber in
the asphalt/fibre slurry 226 is recovered as asphalt and fiber in the
asphalt/fiber mixture 212,
or more than 85% wt.%, or more than 90% wt.%, or more than 95% wt.%, or more
than 98%
wt.% of the total weight of asphalt and fiber in asphalt/fibre slurry 226 is
recovered as asphalt
and fiber in the asphalt/fiber mixture 212.
[0087] Generally speaking, the asphalt/fiber mixture 212 will have a
fluid content that
is less than the fluid content of the asphalt/fiber slurry 226. According to
one embodiment,
when the fluid is water, the asphalt/fiber mixture 112 can contain less than
about 1 wt.% water,
based on the total weight of the asphalt/fiber mixture, for example, less than
about 2 wt.%
water, or less than about 4 wt.% water, or less than about 6 wt.% water, or
less than about 8
wt.% water, or less than about 10 wt.% water, or less than about 12 wt.%
water, or less than
about 14 wt.% water, or less than about 15 wt.% water, based on the total
weight of the
asphalt/fiber mixture.
[0088] As described above, substantially all of the aggregate may be
separated from
the roofing shingles 202, such that the asphalt/fiber mixture 212 is
substantially free of
aggregate. In one embodiment, the asphalt/fiber mixture may contain less than
about 5 wt.%
of aggregate, based on the total weight of the asphalt/fiber mixture. In other
embodiments,
the asphalt/fiber mixture may contain less than about 4 wt.%, or less than
about 3 wt.%, or
less than about 2 wt.%, or less than about 1 wt.%, based on the total weight
of the asphalt
fiber mixture. Accordingly, the aggregate removal unit 204 may be operable to
remove at
least 95 wt.% of the total weight of aggregate in the roofing shingles 202. In
other
embodiments, the aggregate removal unit 204 may be operable to remove at least
about 96
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Date Recue/Date Received 2022-09-29
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wt.%, or at least about 97 wt.% or at least 98 wt.% or at least 99 wt.% of the
total weight of
aggregate in the roofing shingles 202.
Separation of Fiber Step (106) in Fiber Separation Unit (206)
[0089] As described above, in step 106, fiber may be separated from
the asphalt/fiber
mixture 112 by adding a solvent 114 to the asphalt/fiber mixture 112 to form
the
asphalt/fiber/solvent slurry 134 and machine pressing the slurry to remove
fiber from the slurry
to produce an asphalt/solvent mixture 118 and a fiber product 116. In the
embodiment shown
in FIG. 2, this separation may be accomplished in the fiber separation unit
236 by adding
solvent 230 to the asphalt/fiber mixture 212 in mixing tank 232 to form an
asphalt/fiber/solvent
slurry 234 and separating fiber from the asphalt/fiber/solvent slurry 234 in
the fiber separator
236 to produce an asphalt/solvent mixture 216 and fiber product 214. In one
embodiment,
step 106 is performed in the fiber separation unit 206 at ambient temperature.
[0090] The mixing tank 232 may be any suitable container or vessel
configured to
receive and mix the solvent 230 and asphalt/fiber mixture 212 to form the
asphalt/fiber/solvent
slurry 216 and holding the slurry therein. The mixing tank 232 may include any
mixing device
suitable for mixing described above, such as a paddle, impeller or a
recirculation pump to
improve the contact between the solvent 230 and asphalt/fiber mixture 212.
[0091] The solvent 230 may be any suitable solvent or blend of more
than one solvent.
In one embodiment, the solvent 230 may be at least one solvent that is
miscible with asphalt.
The solvent 230 may perform some or all of the beneficial functions as
outlined below when
introduced into the mixing tank 232. Firstly, the solvent 230 may act as a
release agent to
strip or remove asphalt coating the fiber in the asphalt/fiber mixture 212
(i.e. the fiber in the
asphalt/fiber/solvent slurry 134 may become substantially free from adhered
asphalt). The
solvent 230 may also act as a co-solvent/diluent for the asphalt/fiber mixture
212 which will
beneficially reduce the viscosity of the asphalt/fiber/solvent slurry 234. As
such, the
asphalt/fiber/solvent slurry 234 may include a liquid phase that is a solution
of solvent and
asphalt with a solid phase of fiber. Furthermore, the solvent 230 may be
selected from a
group of solvents having a boiling point that enables easier solvent
separation in step 108.
23
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[0092] In one embodiment, the solvent 230 may comprise an aromatic
solvent, which
refers to a solvent comprising at least one aryl group. The term "aryl" as
used herein, whether
it is used alone or a part of another group refers to cyclic groups that
contain at least one
aromatic ring. In an embodiment, the aromatic solvent is benzene, toluene,
ortho-xylene,
meta-xylene, para-xylene, ethylbenzene or trimethylbenzene.
[0093] In another embodiment, the solvent 230 comprises an aliphatic
solvent or
blend of more than one aliphatic solvent such as a straight or branched chain
C4-C30 alkane
or C4-C40 olefin. In one embodiment, the aliphatic solvent, is butane,
pentane, cyclopentane,
hexane, cylcohexane, heptane, octane, nonane, decane, undecane or dodecane, or
a terpene
such as limonene. In other embodiments the aliphatic solvent may be any
suitable blend of
more than one aliphatic solvents such as gasoline, diesel, petroleum
distillate, petroleum
ether, mineral spirits, naptha, kerosene or turpentine.
[0094] In another embodiment, the solvent 230 comprises a halogenated
solvent, that
is a solvent containing at least one halogen atom, such as dichloromethane,
1,1,1-
trichloroethylene, tetrachloroethylene, n-propylbromide, chlorohexane, carbon
tetrachloride or
chloroform.
[0095] In another embodiment, the solvent 230 comprises a suitable
alcohol, such as
a straight or branched chain C1-C10 alcohol or mixture thereof. In an
embodiment the C1-C10
alcohol is ethanol, butanol, propanol, isopropanol (IPA). The alcohol may
comprise an
aromatic alcohol, which refers to an alcohol comprising an aryl group as
defined above, such
as benzyl alcohol.
[0096] In an embodiment, the solvent 230 comprises an ether, such as
tetrahydrofuran, diethyl ether, 1,2-dioxane, 1,3-dioxane or 1,4-dioxane,
methoxybenzene.
[0097] In another embodiment, the solvent 230 comprises a ketone, for
example a C3-
C12 ketone such as acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone,
or methyl
acetate.
[0098] In another embodiment, the solvent 230 is carbon disulfide.
24
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[0099] The solvent 230 may be added to the mixing tank 232 in any
suitable mass
fraction relative to the asphalt/fiber mixture 212. For example, the mass
fraction of solvent
230 that is added to the asphalt/fiber mixture 212 may be selected such that
substantially all
of the asphalt in the asphalt/fiber mixture 212 coating the fiber is released
so substantially all
of the asphalt in the asphalt/fiber/solvent slurry 234 is in the liquid phase.
Further, the solvent
230 may be added such that the asphalt/fiber/solvent slurry 234 is flowable at
ambient
temperature.
[00100] In one embodiment, the mass fraction of solvent 230 added to
the asphalt/fiber
mixture may be in the range of about 15-50 wt.% relative to the total weight
of the asphalt/fiber
mixture 212. In another embodiment, the amount of the solvent 230 added to the
asphalt fiber
mixture is an amount of greater than about 15 wt.% relative to total weight of
the asphalt/fiber
mixture 212, for example, greater than about 20 wt.%, greater than about 25
wt.%, greater
than about 26 wt.%, greater than about 27 wt.%, greater than about 28 wt.%,
greater than
about 29 wt.%, greater than about 30 wt.%, greater than about 31 wt.%, greater
than about
32 wt. %, greater than about 33% water, greater than about 34 wt.% water,
greater than about
35 wt.% water, greater than about 40 wt.% water, greater than about 45 wt.%
water, or greater
than about 50 wt.%, relative to the total weight of the asphalt/fiber mixture
212.
[00101] The asphalt/fiber/solvent slurry 234 is then sent to and
received by the fiber
separator 236 to separate the fiber from the slurry. The fiber separator 236
may be any
.. suitable piece of equipment or apparatus that is operable to separate fiber
from the
asphalt/fiber/solvent slurry 234, such as a machine press (mechanical press)
or a filter press.
For example, the fiber separator 236 may be a rotary press, belt press,
hydraulic press, piston
press, hydrocyclone or a centrifuge.
[00102] In one embodiment, the fiber separator 236 is a screw press,
also commonly
referred to as a dewatering screw press, which is operable to separate fiber
from the
asphalt/fiber/solvent slurry 234. The screw press is known and may include one
or more
screws (also known as an Archimedean screw) which is rotatable within a
housing. The screw
may include a central shaft about which is wound a spiral steel plate.
Material, in this case
the asphalt/fiber/solvent slurry 234, may be sent to and received by an inlet
of the screw press.
As the screw rotates, for example when driven by an electrical motor, the
slurry 234 within the
Date Regue/Date Received 2022-09-29
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housing will move towards the opposite end of the inlet (i.e., discharge end)
of the housing.
As the slurry 234 moves from the inlet end to the discharge end, the cavity
size in which the
slurry 234 is contained decreases such that the slurry therein is compressed.
This reduction
in cavity size may be due to a taper on the central shaft of the screw such
that the diameter
of the shaft increases towards the discharge end. Additionally or alternately,
the separation
between the flights of the spiral steel plate may decrease towards the
discharge end of the
screw press in order to compress the slurry 234 between the flights towards
the discharge
end.
[00103] The housing may be made from a permeable material, such as a
screened
surface, a perforated sheet, a sintered screen or a wedge wire screen that, as
the slurry 234
is compressed therein, the internal pressure generated within the housing
forces asphalt and
solvent to be discharged through the permeable material. The permeable
material may be
selected such that substantially only asphalt and solvent will pass through
the permeable
material and not fiber or other solid particles from the asphalt/fiber/solvent
slurry 234. In this
example, the liquid (or filtrate or liquor) passing through the permeable
material is the
asphalt/solvent mixture 216.
[00104] The remaining solid fiber material, which does not pass
through the cylindrical
housing is conveyed towards the discharge end of the screw press by the
rotational action of
the screw and may be recovered at the discharge end as the fiber product 214
commonly
called the press cake or filter cake.
[00105] In comparison to other fiber separators, a screw press is well
suited to process
relatively viscous materials, such as the asphalt/fiber/solvent slurry 234. A
screw press may
also advantageously operate in continuous manner with a high throughput and is
less
susceptible to clogging/blockages in comparison to other fiber separators.
[00106] In some embodiments, either or both of the screw press or the
asphalt/fiber/solvent slurry 234 may be at ambient temperature or at an
elevated temperature.
[00107] In and embodiment the screw press may be a twin screw press,
which includes
two opposed, intermeshing screws configured to rotate in opposite directions
relative to each
other.
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[00108] The fiber product 214 that is separated from the slurry 234
and recovered from
the fiber separator 236 may be substantially free of asphalt. In one
embodiment, the fiber
product 214 may have less than about 20 wt.% of asphalt, based on the total
weight of the
fiber product 214. In other embodiments, the fiber product 214 may have less
than about 15
wt.%, or less than about 10 wt.% or less than about 9 wt.% or less than about
8 wt.% or less
than about 7 wt.% or less than about 6 wt.% or less than about 5 wt.% or less
than about 4
wt.% or less than about 3 wt.% or less than about 2 wt.% or less than about 1
wt.% of asphalt,
based on the total weight of the asphalt product 214.
Recovery of Asphalt Step (108) in Solvent Separation Unit (208)
[00109] As described above, in step 108 solvent may be separated from the
asphalt/solvent mixture 116 by heating the mixture to separate the solvent
from the mixture to
produce an asphalt product 118. In the embodiment shown in FIG. 2, this
separation may be
accomplished in the solvent separation unit 208 by passing the asphalt/solvent
mixture 216
through the solvent separator 238 to produce the asphalt product 218.
[00110] In one embodiment, the solvent separator 238 may be any suitable
distillation
unit or evaporator such as, for example a fractional distillation unit, a
short path distillation
unit, a 2-stage distillation unit, a disc and donut distillation unit or a
spinning band distillation
unit operable to separate solvent from the asphalt/solvent mixture 216. The
solvent separator
238 may operate at atmospheric or reduced pressure as required. In another
embodiment,
the solvent separator 238 may be an evaporator, such as thin film evaporator,
which may
include a falling film evaporator or a wiped film evaporator. In another
embodiment, the
solvent separator 238 may be a heated stirred tank such as a commonly known
continuous
stirred tank reactor (CSTR).
[00111] In other embodiments, the solvent separator operates at
atmospheric pressure
and at a temperature of about 75 C or greater. In one embodiment, the solvent
separator
operates at atmospheric pressure and a temperature of about 77 C.
[00112] In one preferred embodiment, the solvent separator 238 is a
wiped film
evaporator (WFE), also known as a wiped film distillation unit. The WFE may
include a
vertically orientated cylinder with an internal rotor driven wiper. The wiper
may include a single
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blade or a plurality of stacked blades that may be offset and/or overlap with
respect to each
other. In an embodiment the WFE may have 32 blades. The cylinder may be
externally
heated, such as by a surrounding heated jacket. The asphalt/solvent mixture
216 may be
introduced at the upper end of the cylinder and the wiper may distribute the
mixture to create
a thin film of the mixture on the inner surface of the cylinder. As the
mixture 216 spirals down
the inner surface of the cylinder, the solvent within the mixture is readily
evaporated.
[00113] The distillate vapor (i.e., solvent) may be condensed and
collected in an
internal condenser running down the center of the cylinder. In other
embodiments, the
distillate vapor may flow out of either the top or bottom of the WFE and may
be condensed in
an external condenser.
[00114] The concentrate (i.e., asphalt 118) does not evaporate under
these conditions
and will run down the inner surface of the cylinder and be recovered as the
asphalt product
218 at the lower end of the cylinder where it may be transferred, for e.g., to
a storage tank or
rail car or road tanker, for further processing/repurposing.
[00115] The WFE may operate at about 10 C to about 50 C above the boiling
point of
the solvent being used and at about 10 C to about -50 C below the lowest
boiling point
component of the asphalt. The WFE may operate under a vacuum which may be
least about
0 mmHg up to a slight positive pressure of about 30 psia (i.e., from about 0
atm to about 2
atm). In one example embodiment, when the solvent 230 is toluene, the WFE may
operate at
.. a temperature of about 155-165 C and at atmospheric pressure.
[00116] In an embodiment, the WFE operates at a temperature between
about 120 C
and about 200 C and at atmospheric pressure.
[00117] The solvent that is condensed and recovered from the solvent
separator 236
may be substantially free of asphalt and other impurities and may be recycled
back to mixing
tank 232, as shown in FIG. 2.
[00118] The asphalt product 218 may be recovered from the solvent
separator 238 in
high yield and purity and may be substantially free of fiber, solvent and
fluid 224. According
to one embodiment, the asphalt product 218 can contain less than about 1 wt.%
of fiber and/or
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solvent and/or fluid 224, based on the total weight of the asphalt product,
for example less
than about 2 wt.%, less than about 3 wt.%, less than about 4 wt.% or less than
about less
than about 5 wt.%, based on the total weight of the asphalt product.
[00119] In an embodiment where asphalt/solvent mixture 216 contains a
proportion of
water and where solvent 230 is toluene, the toluene and water within
asphalt/solvent mixture
261 may form an azeotropic mixture. As is known, an azeotropic mixture may
have a boiling
point that is lower than either of its constituents. As such, depending on the
composition of
the azeotropic mixture the solvent separator 238 (such as a WFE) may operate
at a lower
temperature.
[00120] The overall recovery of the asphalt product 218 from the roofing
shingles 202
may be highly efficient such that a large proportion of the asphalt that was
present in the
roofing shingles 202 when the roofing shingles are added to the separation
tank 222 is
recovered as asphalt product 218. According to one embodiment, at least about
80 wt.% of
the total weight of asphalt in the roofing shingles 202 is recovered as
asphalt product 218, for
example at least about 82 wt.%, at least about 84 wt.%, at least about 86
wt.%, at least about
88 wt.%, at least about 90 wt.%, at least about 92 wt.%, at least about 94
wt.%, at least about
96 wt.%, at least about 98 wt.% at least about 98 wt.% of the total weight of
asphalt in the
roofing shingles 202 is recovered as asphalt product 218.
[00121] In another embodiment, the present disclosure provides a
process for recycling
asphalt-based roofing materials wherein the units of such a process are
completely integrated,
and thus the process is of low cost, economical and versatile due to the
alternatives and
interconnections within their steps. The integrated process is more energy
efficient and
materials efficient than the individual processes together, and, as such,
yields a higher
productivity.
[00122] According to one embodiment, the integrated process of the present
disclosure
relates to an integrated process for recycling asphalt-based roofing shingles
to produce an
aggregate product, a fiber product and an asphalt product. The integrated
process may
include a step of contacting the asphalt-based roofing shingles with at least
one pressurized
stream of fluid in a separation tank to separate aggregate from the roofing
shingles to produce
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an asphalt/fiber slurry and the aggregate product as described above. Moisture
is then
removed from the asphalt/fiber slurry in a dewatering or drying apparatus to
produce an
asphalt/fiber mixture. The moisture that is removed in the drying apparatus
may be recovered
and recycled back to the separation tank.
[00123] The integrated process also includes a step of adding a solvent to
the
asphalt/fiber mixture produced above in a mixing tank to produce an
asphalt/fiber/solvent
slurry. Fiber is separated from the asphalt/fiber/solvent slurry in a fiber
separator to produce
an asphalt/solvent mixture and the fiber product.
[00124] The integrated process also includes a step of separating
solvent from the
asphalt/solvent mixture produced above in a solvent separator to produce the
asphalt product.
Solvent separated from the asphalt/solvent mixture may be recovered and
recycled back to
the mixing tank.
[00125] The integrated process described above may run batch-wise or
continuously
where roofing shingles are continuously added to the process while the
aggregate, fiber and
asphalt products are continuously produced and collected. The fluid and
solvent that are
recovered may be continuously reused within the integrated process as
described above such
that additional fluid and solvent may not need to be required to be added
during continuous
operation. In some embodiments a small amount of fluid and/or solvent may need
to be added
to account for any losses during the process.
[00126] Accordingly, the products made in the method, integrated process
and system
described herein may be suitable for a use in variety of applications. By way
of example, the
aggregate product may be used in asphalt concrete for paving and road
surfaces, in the
manufacture of new asphalt-based roofing materials, as a blasting material (or
media) in
sandblasting and in other general construction materials.
[00127] When the roofing shingles include paper fiber, the fiber product
may have a
high BTU value and may be suitable for use as an engineered fuel. The fiber
product may
beneficially contain a trace amounts of combustible organics, such as solvent
and/or asphalt
which may increase the BTU value of the fiber product. In one embodiment, the
fiber product
may be used as an engineered fuel, such as for a cement production facility.
Date Recue/Date Received 2022-09-29
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[00128] When the roofing shingles include glass fiber, the fiber
product may be
incorporated into the production of new glass fiber materials and products. In
another
embodiment, the fiber product may be used in patching kits for repairing fiber
glass structures,
such as boats and kayaks. In one embodiment, the fiber product may be further
processed
by mechanical grinding or milling to reduce its particle size to a fine powder
that may be
incorporated as a filler or reinforcing material for products such as
artificial wood, cement or
asphalt concrete.
[00129] The asphalt product produced herein may be of a similar
quality to refined (or
virgin) asphalt and may be suitable for any application where refined asphalt
is used. For
example, the asphalt may be suitable for blending with virgin asphalt for any
application where
refined asphalt is used. For example, the asphalt product may be used in
asphalt concrete
for paving and road surfaces, in the manufacture of new asphalt-based roofing
materials and
sealing and insulating a variety of building materials, such as pipe coatings
and carpet tile
backing.
[00130] In an embodiment, the asphalt produced herein may have a
penetration grade
of between about 8 and about 50 decimillimeters (dmm), as measured by the
American
Society for Testing and Materials (ASTM) D5-06 standard test method.
[00131] In an embodiment, the asphalt produced herein may have a
softening point of
between about 80 C and about 120 C or greater as measured by the ASTM D36-95
standard
test method.
[00132] In an embodiment, the asphalt produced herein may have a flash
point of
between about 180 C and about 300 C or greater as measured by the ASTM D92-05a
standard test method.
[00133] In other embodiments, any of the intermediate products
disclosed herein, such
as the asphalt/fiber slurry, the asphalt/fiber mixture, the
asphalt/fiber/solvent slurry and the
asphalt/solvent mixture, may be collected and transported to another location
for further
processing, which may include the steps described above or different method
steps to
produce any of the product described above.
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[00134] For example, in one embodiment, the asphalt/solvent mixture,
rather than
entering the solvent separator, may be transported, such as by tanker truck,
rail or pipeline
for further use, storage or processing. The presence of the solvent in the
mixture may
beneficially act as a diluent to lower the viscosity of the asphalt/solvent
mixture simplifying the
handing and transport of the mixture, especially while at lower temperatures.
In one
embodiment, the asphalt/solvent mixture may be transported to another facility
where the
solvent may be separated from the mixture by a solvent separator described
above to produce
an asphalt product.
[00135] Although making and using various embodiments of the present
disclosure
have been described in detail above, it should be appreciated that the present
disclosure
provides many applicable inventive concepts that can be embodied in a wide
variety of specific
contexts. The specific embodiments discussed herein are merely illustrative of
specific ways
to make and use the invention, and do not delimit the scope of the invention.
32
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